Mains phase detection apparatus

Abstract

The present invention relates to an apparatus for accurately detecting a mains phase. The apparatus is constructed with a zero-crossing detector, a digital phase detector, a digital loop filter, and a digital controlled oscillator (DCO) of a direct digital synthesized (DDS) manner. The present apparatus employs an all-digital loop architecture and a high sampling clock to recover a signal with a phase orthogonal with the mains signal and a frequency the same as the mains signal. And jitters in the recovered signal are less than 10 us. The present apparatus is capable of implementing signal tracking of a zero frequency error and a zero phase in a wide range, and can provide a detection result of excellent performance for the power line carrier communication, mains frequency detection, etc.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application represents the national stage application of International Application PCT / CN2006 / 003082, filed 16 Nov. 2006, which claims the benefit of Chinese Patent Application 200510110391.3, filed 16 Nov. 2005, which is incorporated herein by reference in its entirety for all purposes.TECHNICAL FIELD[0002]The present invention relates to a phase detection apparatus, more particularly to a mains phase detection apparatus.BACKGROUND OF THE INVENTION[0003]It is required to detect the phase / frequency of a power line in various application fields, such as mains frequency monitoring, phase-controlled rectification, and mains phase detection in a power line carrier communication.[0004]A zero-crossing detection method is employed by conventional mains phase / frequency detection, i.e., a zero-crossing point is detected by a comparator, and a cycle and a frequency of the mains are then obtained by calculating the time interval between zero-cr...

AI Technical Summary

Benefits of technology

"The present invention provides a mains phase detection apparatus with a high precision. The apparatus includes a zero-crossing detector and an all-digital phase-locked loop (ADPLL) with a digital phase detector, digital loop filter, and digital controlled oscillator. The apparatus has a high detection precision for the mains phase. The technical effects of the invention include improved detection precision, reduced detection errors, and improved reliability."

Problems solved by technology

However, since there is a large amount of noise and interference on the power line, the appearing time of the zero-crossing points will be affected, which thus causes it is impossible to obtain a detecting result with a high precision from such a simple zero-crossing detection method.

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